Ken, I used the typical painter's duster, a retired paint brush with the handle cut off for a back pocket fit. I generally don't like the idea of introducing any solvent to a surface between coats of finish, even water. Reason being that even though the surface is dry to recoat, the coating is not cured and could be reactivated. The second coat reactivates it but it's apples to apples. Dusting off a vertical when recoating is more than adequate in my book, and the only time I do a tack process is on furniture grade horizontals, like built-ins, or knee wall tops, etc.
The only thing I know from my experience that clouds clear finishes is humidity (moisture), temp drops?, or possibly recoating too soon, that's why I asked if that could be sweat drops or splashes of thinner. Trapped moisture.
I would call the Minwax tech department, quizz them and find what they recommend as a solution. Good Luck.
Edit: When you run your finger across them is there any roughness, texture?
There is some roughness. I assume that is very fine dust particles in the basement. I can call Minwax again. They are the ones who recommended the mineral spirits before and in between coats of poly.